SALT LAKE CITY -- More than 165 million tons of rock and dirt came crashing into one of the world's largest open pits in last week's massive landslide that halted operations at a Utah copper mine.
Kennecott Utah Copper officials released the estimate Tuesday. They also said that they expect copper production at the Bingham Canyon Mine southwest of Salt Lake City will only be half of what was expected this year due to the April 10 landslide, the largest in the history of the mine.
"It was a significant slide," Bennett said.
Two-thirds of the floor of the mile-deep pit was covered by the dirt and rocks, burying some of the company's dump trucks. Officials anticipated the slide and pulled the 37 workers from the area. No one was injured.
There's no estimate of how much the landslide will cost the mine, said company spokesman Kyle Bennett. But they do know that three of the company's 13 shovels and 14 of its 100 trucks were damaged. Some bulldozers and graders were also damaged, Bennett said. How much of the equipment is salvageable is unknown.
"We're optimistic that some of them will only require minor repair," Bennett said.
The company doesn't know when the mine will reopen.
Work resumed Sunday in an area not affected by last week's slide, but there's still a lot of work to be done before operations can resume elsewhere, Bennett said. First, company officials need to assess damage to buildings and equipment. Then, they need to move the rocks and dirt and recreate roads.
Hundreds of mine workers at Kennecott Utah Copper are being asked to take voluntary vacation or unpaid leave. Workers who don't want to take time off will be assigned to jobs outside their usual roles at the Bingham Canyon Mine, Bennett said.
Dell Garnder, a heavy haul truck driver at the mine, told KSL-TV that it may take as long as two years to dig out all the material. But Bennett said he believes the mine will recover.
"We are doing everything we can to get production back up and going," Bennett said. "We're less than a week removed from this major slide. We need to continue to make logical and methodical decisions about the operation."
The estimated number of tons that slid down is based on laser scanners in the mine and visual observations, Bennett said. Federal regulators have not allowed the company's geotechnical experts to go into the pit to closely assess damage.
About 800 people work at the mine, and there are a total of 2,500 employees within the entire operation, Bennett said. The mine is one of the biggest producers of copper in the country.
For more than a century, miners have wilted down a mountaintop about 20 miles southwest of Salt Lake City to a deep hole nearly a mile deep. Miners have dug into a tooth-shaped volcanic core that has yielded millions of tons of copper and small amounts of gold and silver. Kennecott is the latest in a succession of owners.
Normally, Kennecott operates the mine all day, every day, with electric-powered shovels capable of scooping up 98 tons of crushed rock at a bite. The company continues to operate a copper concentrator, refinery and smelter.
The landslide tore loose not far from a visitor center on the rim of the pit closed earlier this month as a precaution.